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Ivan Scheblykin. Portrait.

Ivan Scheblykin

Professor

Ivan Scheblykin. Portrait.

Photo-Oxidation Reveals H-Aggregates Hidden in Spin-Cast-Conjugated Polymer Films as Observed by Two-Dimensional Polarization Imaging

Author

  • Juanzi Shi
  • Xiaofeng Xu
  • Yuxin Xia
  • Ruiyun Chen
  • Zafer Hawash
  • Dargie Deribew
  • Ellen Moons
  • Olle Inganäs
  • Ivan G. Scheblykin

Summary, in English

Spin-cast intermolecular interactions in conjugated polymer films lead to the formation of excited states delocalized over a few oriented and tightly packed conjugated segments. The optoelectronic properties of conjugated polymers are strongly dependent on the presence of such oriented domains at a nanoscale level. We observe oriented domains as large as several micrometers in size spontaneously formed in spin-cast PBDT-TPD films. Two-dimensional polarization imaging of fresh and photodegraded films showed a much higher visibility of the oriented domains in the degraded samples. We propose that the film is a mixture of two phases with different degrees of chain alignment. The photoluminescence of the more anisotropic phase is more stable against photodegradation in comparison with the less anisotropic phase. Photodegradation predominately quenches photoluminescence of the less anisotropic phase making the oriented domains more visible in the polarization contrasts. Spectral and energy transfer properties of the more oriented phase allowed us to assign it to weakly coupled H-aggregates with the suppressed 0-0 vibronic transition. Stable photoluminescence of H-aggregates in comparison with that of nonaggregated (less oriented) chains may help to understand degradation mechanisms of polymer devices and shows the role of energy transfer in this process. Selective degradation-induced quenching can reveal hidden inhomogeneity of conjugated polymer films.

Department/s

  • Chemical Physics
  • NanoLund: Centre for Nanoscience

Publishing year

2019

Language

English

Pages

8927-8936

Publication/Series

Chemistry of Materials

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Materials Chemistry
  • Atom and Molecular Physics and Optics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0897-4756